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1.
Fatemeh Paborji Mahdi Shafiee Afarani Amir Masoud Arabi Mehdi Ghahari 《International Journal of Applied Ceramic Technology》2022,19(5):2406-2418
Solution combustion synthesis of iron chromite was reported using iron(III) nitrate nonahydrate and chromium(III) nitrate nonahydrate as starting materials, as well as glycine, urea, citric acid, and ethylene glycol as fuels. The influence of fuel type on the structure, molecular, microstructure as well as chromatic properties of samples was investigated. The X-ray diffraction (XRD) patterns showed that unlike themodynamical prediction, glycine fuel led to strongest combustion and consequent highest XRD peak intensities and lower lattice parameters. Moreover, the change of fuel type and mixing of fuels affected XRD data. Fourier transform infrared analysis showed that the band position of Cr–O and Fe–O bonds were shifted to higher frequencies by using of fuels with weaker combustion reactions. In addition, scanning electron micrographs showed that different morphologies of FeCr2O4 particles were obtained depending on the fuel type and ratios. Energy-dispersive X-ray spectroscopy analysis of the samples showed that oxygen concentration of samples was less than that of stoichiometric ratio of FeCr2O4 due to local reducing atmosphere. Furthermore, chromatic properties of the powders showed that the pigment synthesized with glycine fuel has a better and lighter grayish brown color than the other ones and can be used as a suitable industrial candidate to create a brown color in the ceramic glaze. 相似文献
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Fatemeh Paborji Mahdi Shafiee Afarani Amir Masoud Arabi Mehdi Ghahari 《International Journal of Applied Ceramic Technology》2023,20(2):1154-1166
Iron chromite pigment was synthesized via solution combustion using iron(III) nitrate nonahydrate and chromium(III) nitrate nonahydrate as starting materials, and glycine, urea, citric acid, and ethylene glycol as fuels. The effect of postheating temperature on the structure, microstructure, and chromatic properties of the synthesized powders was also studied. X-ray diffraction patterns showed that the as-synthesized powders were amorphous to crystalline FeCr2O4 phases, depending on fuel type. Moreover, regardless of the fuel type, postheating led to the d-space shift and oxidation and formation of (Fe,Cr)2O3 solid solution. Phase transformation of FeCr2O4 to (Fe,Cr)2O3 solid solution was observed at 500/750°C depending on the dominant phase present in the as-synthesized particles. Fourier transform infrared analysis illustrated a shift in the band position of octahedral M–O and tetrahedral M–O bonds due to the movement of Fe cations and the lattice shrinkage by increasing the postheating temperature. Moreover, scanning electron micrographs showed that Fe0.7Cr1.3O3 semispherical fine particles consisted mainly of porous and spongy FeCr2O4 particles due to the oxidation and phase transformation during postheating. According to chromatic measurements, the ink prepared by using the powders synthesized in the presence of glycine and post-heated at 500°C showed reddish-brown color which could be considered a promising candidate for tile decoration application. Furthermore, rheology studies revealed that the prepared ink showed non-Newtonian shear thinning behavior. 相似文献
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以硝酸铬和硝酸铜为原料兼氧化剂,甘氨酸、乙二醇和尿素为还原剂,采用液相燃烧法合成CuCrO2,并将其与n型半导体物质WO3复合后得到的(CuCrO2-WO3)复合催化剂用于光催化产氢实验。通过X射线衍射(XRD)、扫描电子显微镜、紫外–可见漫反射光谱(UV-vis DR)及光催化活性测试,考察了燃烧剂类型和用量对合成CuCrO2的物相组成、微观形貌、吸光性能和光催化性能的影响。结果表明:采用甘氨酸为燃烧剂,且甘氨酸与金属离子的摩尔比为1.4:1的条件下制备的CuCrO2性能较优,其粒径较小,分散均匀;其复合后的催化剂(CuCrO2-WO3)光催化产氢活性较高。探讨了燃烧法合成CuCrO2时物质的转化过程。XRD分析表明,硝酸盐与燃料经剧烈燃烧反应主要得到小颗粒的Cu2O和Cr2O3,后经固相反应制得较为理想的CuCrO2晶体颗粒。 相似文献
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《Ceramics International》2020,46(14):22313-22320
Design of high-performance electromagnetic (EM) wave absorbing materials has been regarded as an effective solution to excessive EM wave interference problem. As a promising candidate, NiCo2O4 absorbers have attracted enormous research attentions. However, currently reported morphology-manipulation synthetic methods of NiCo2O4 absorbers are time-consuming and require high energy consumption, which inhibit their practical applications. Herein, a more facile and cost-effective solution combustion synthesis was utilized to fabricate NiCo2O4 materials. The absorber prepared by using glycine as fuel displayed the best EM wave absorption performance. Impressively, ultra wide absorption bandwidth of 7.44 GHz from 10.56 GHz to 18 GHz could be achieved with relatively thin thickness of 2.1 mm NiCo2O4 sample fabricated in this work displayed the widest effective absorption bandwidth (EAB) among reported NiCo2O4-based EM wave absorbing materials so far. In view of its simple and low-cost synthetic process and excellent EM wave dissipation capacity, NiCo2O4 samples in this work showed great feasibility as practical absorber. In addition, our findings may also provide new sight for facile preparation of other high-performance EM wave absorbers by solution combustion synthesis instead of complex morphology-manipulation routes. 相似文献
6.
纳米MgAl2O4粉体的溶液燃烧合成及烧结性能 总被引：2，自引：0，他引：2
以氨基乙酸和尿素为燃料,用溶液燃烧合成法制备了 MgAl2O4 纳米粉体,并研究了氨基乙酸和尿素的摩尔比(0:1,2:9 和 1:1)对粉体特性和烧结性能的影响。对粉体的扫描电子显微照片分析发现:用两种混合燃料制备的 MgAl2O4 粉体呈多孔状结构,且实验所用混合燃料有利于 MgAl2O4粉体的分散。结果表明:颗粒(团聚体)的平均粒径随所用燃料中氨基乙酸含量的增加而明显减小,粉体的比表面积随氨基乙酸含量的增加而显著增大,表明所用的混合燃料能显著降低 MgAl2O4粉体的团聚程度。此外,MgAl2O4粉体的烧结性能随所用燃料中氨基乙酸含量的增加而显著提高。 相似文献
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以硝酸钴、硝酸铜、硝酸锰和硝酸铁为氧化剂及DL-丙氨酸为燃料,采用溶液燃烧法合成(Co_(0.5)Cu_(0.5))(MnFe)O_4纳米晶黑色陶瓷色料。采用同步热分析仪对反应前驱体进行热性能分析,采用X射线衍射仪、扫描电子显微镜、分光光度计等手段对样品的物相、晶粒尺寸、颗粒形貌及尺寸、色度进行表征。结果表明:当丙氨酸与硝酸盐类之比按推进剂化学理论计算为化学计量比时,反应体系在230℃可以完成反应,且点火温度越高越有利于产物形成;当丙氨酸与硝酸盐类之比为化学计量比和点火温度为400℃时,样品的结晶度好,其晶粒和颗粒平均粒径分别为16.4nm和1μm,同时,样品无需后续煅烧在透明基础釉中有良好的着色力。另外,还研究了加入惰性盐氯化钾对合成产品的影响,结果表明,加入氯化钾合成样品的分散性好,其晶粒和颗粒平均粒径分别为10.8nm和300 nm,同时,其着色力比未加氯化钾合成样品的着色力有较大提高。 相似文献
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It is quite common for computer‐controlled displays to emit light in image areas set to digital values of zero, referred to as their black level. This is expected for liquid–crystal displays and also can occur for cathode‐ray tube displays when the “brightness” (gun‐amplifier offset) is set excessively high. For either display, the light emission at the black level results in color channels whose chromaticities vary with luminance level. Consequently, typical methods of colorimetric characterization result in large error. When this black‐level emission is measured and accounted for suitably, characterization accuracy is dramatically improved. Unfortunately, many instruments used to measure displays have too low a sensitivity to measure black‐level emission with sufficient precision and accuracy. A method of estimating black‐level emissions was derived and tested. Because the optimal black‐level results in channel chromaticities that are invariant to the greatest extent with luminance level, an objective function was defined as the sum of chromaticity variances of each channel over a range of measurements. Minimizing this objective function resulted is an estimate of a display's black level. The estimated black level resulted in equivalent or superior performance to direct measurements. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 379–383, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10181 相似文献
10.
Kamal I Aly 《Polymer International》1999,48(9):773-780
A novel series of polyurethanes was prepared via step-growth solution polymerization, by reaction of arylidene monomers, e g 2,5 bis(4-hydroxybenzylidene)cyclopentanone ( I ), 2,5-divanillylidenecyclopentanone ( II ), 2,6-bis(4-hydroxybenzylidene)cyclohexanone ( III ), 2,6-divanillylidenecyclohexanone ( IV ) or 2,7-bis(4-hydroxybenzylidene)cycloheptanone ( V ) with diisocyanates such as toluylene diisocyanate and methylene bis(4-phenylisocyanate). To characterize these polymers, the corresponding model compounds were prepared from monomers I–V and phenylisocyanate. The polymers were characterized by reduced viscosity measurements, IR spectroscopy, 1H NMR, solubility and determination of their crystallinity. Characterization of the model compounds was accomplished by elemental analysis, IR and 1H NMR spectroscopy. The thermal stabilities of the polymers were evaluated by thermogravimetric analysis. The morphology of one of these polymers was examined by scanning electron microscopy. © 1999 Society of Chemical Industry 相似文献
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用柠檬酸(C6H8O7·H2O,citric acid,CA)做还原剂,硝酸盐做氧化剂,利用溶胶-凝胶低温燃烧合成工艺制备Ce0.8Y0.2O1.9纳米固溶体.用X射线衍射、红外光谱研究CA用量、前驱体溶液的pH值对溶胶-凝胶形成的影响.利用差热-热重分析仪、透射电镜及X射线衍射仪分析凝胶的分解及产物的微观结构.结果表明:络合物之间是通过氢键的方式凝胶化的,控制CA的用量、溶液的pH值可以获得稳定的凝胶.改变氧化剂的用量可以获得颗粒尺寸为5～40 nm的Ce0.8Y0.2O1.9超细粉体. 相似文献
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以固态氮化剂燃烧合成AlN-SiC固溶体的研究 总被引：1，自引：0，他引：1
通过热爆方式点燃铝粉、氮化硅粉、碳黑的混合粉末压坯,在较低氮气压力下成功地合成了ＡｌＮ－ＳｉＣ固溶体陶瓷．研究了气体环境、氮气压力对燃烧特征的影响．结合热力学分析,解释了ＡｌＮ－ＳｉＣ固溶体的形成机理及反应次序．通过扫描电镜,观察了反应物的形貌特征 相似文献
13.
Zahra Ghahramani Amir Masoud Arabi Mahdi Shafiee Afarani Mohammad Mahdavian 《International Journal of Applied Ceramic Technology》2020,17(3):1514-1521
In this study, combustion synthesis of cerium oxide nanoparticles was reported using cerium nitrate hexahydrate as starting material as well as urea, glycine, glucose, and citric acid as fuels. The influence of fuel type on structure, microstructure, band gap, and corrosion inhibition was investigated. X-ray diffraction (XRD) patterns and scanning electron microscopy micrographs showed that CeO2 nanoparticles with different morphologies were obtained depending on the fuel type. Microstructural changes from unreacted gel to sponge-like morphologies were resulted by varying the fuel type from urea, glycine, and glucose to citric acid. In addition to Ce–O bonds, Fourier transform infrared analysis showed carbon bonds of carbonaceous compositions from incomplete combustion which were declined during combustion reaction. Furthermore, corrosion analyses showed that samples synthesized using urea fuel released the most Ce+4 ions and could have better protection than other samples. 相似文献
14.
Fatemeh Paborji Mahdi Shafiee Afarani Amir Masoud Arabi Mehdi Ghahari 《International Journal of Applied Ceramic Technology》2023,20(1):281-293
Iron chromite powders were synthesized via solution combustion route using iron(III) nitrate nonahydrate and chromium(III) nitrate nonahydrate as starting materials, as well as glycine–urea, glycine–citric acid, and glycine–ethylene glycol mixtures as fuels. The effect of postheating at different temperatures on the structure, molecular, microstructure, and chromatic properties of powders and tiles colored by in-glaze powders was studied. The X-ray diffraction patterns showed that as-synthesized powders were obtained in crystalline FeCr2O4 phases moreover, postheating of the powders led to d-space shift and oxidation and formation of (Fe,Cr)2O3 solid solution phase regardless of fuel type. Phase transformation of FeCr2O4 to (Fe,Cr)2O3 solid solution was observed at 500/750°C depending on the dominant phase of as-synthesized particles. Fourier transform infrared analysis illustrated that the band positions of octahedral M–O and tetrahedral M–O bonds were shifted due to Fe cations movement from their position and lattice shrinkage by increasing of post-heating temperature. Moreover, scanning electron micrographs showed that Fe0.7Cr1.3O3 semispherical fine particles were formed from porous spongy FeCr2O4 particles due to oxidation and phase transformation during the postheating. Furthermore, chromatic properties of the samples were represented. The color properties of the pigments showed that the formation of brown pigments is provided with the phase transformation from FeCr2O4 to (Fe,Cr)2O3 at a temperature of up to 750°C. Moreover, increasing the color purity to this temperature is related to the removal of residual carbonaceous matters. The chromatic properties of the glazed tiles colored using the pigments showed that postheating between 250 and 500°C led to more brown appearance. 相似文献
15.
设计合成了一种新型的阴离子探针,1-羟基-4-甲基-二苯甲酮对硝基苯酰腙。通过核磁共振谱、质谱和元素分析对其结构进行表征,利用UV-Vis光谱、荧光光谱及1HNMR研究了受体与阴离子如AcO-、H2PO4-、F-、Cl-、Br-和I-的相互作用。结果表明,在不借助任何其他昂贵仪器的情况下,该探针分子在干燥DMSO溶液中能够较好的比色识别F-、H2PO4-和AcO-离子,结合常数表明,该阴离子受体对AcO-具有较高的选择性和荧光响应。最后通过1HNMR滴定进一步研究了1-羟基-4-甲基-二苯甲酮对硝基苯酰腙与阴离子F-的相互作用的本质。 相似文献
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吡啶氧丁氧苯基三甲氧苯基卟啉及其Fe(Ⅲ)配合物的合成与表征 总被引：3，自引：1，他引：3
报道了一种新型尾式卟啉化合物 - 5 -对 [4- (间吡啶氧基 )丁氧基 ]苯基 - 1 0 ,1 5 ,2 0 -三对甲氧苯基卟啉及其 Fe( )配合物的合成。并通过元素分析、红外光谱、核磁共振光谱及紫外可见光谱等对其结构进行了表征 相似文献
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Nanostructured neodymium doped yttrium aluminum garnet (Nd:YAG) powders were synthesized at low temperature by a gel combustion method with citric acid as fuel and nitrate as oxidizer. The method involves exothermic decomposition of an aqueous citrate–nitrate gel. The decomposition is based on a thermally induced anionic redox reaction. A variety of 1.0 at% Nd:YAG powders with different agglomerate structures were obtained by altering the citrate-to-nitrate ratio γ. The gel with γ = 0.277 yielded nanocrystalline Nd:YAG at 800 °C without the formation of any intermediate phase. For other gels nanostructured Nd:YAG powders were obtained at 850 °C. The gel with γ = 0.1 yielded nanostructured Nd:YAG powder with an average particle size of ∼40 nm. The stoichiometric citrate-to-nitrate ratio (γ = 0.277) gave the lowest amount of agglomeration. The decomposition of the gel was investigated by TG–DSC and FTIR. The produced ashes and calcined powders were characterized by XRD, BET and FETEM analysis. 相似文献
19.
《Ceramics International》2016,42(11):12771-12777
Cobalt oxides nanopowders were prepared using novel cellulose assisted combustion synthesis and solution combustion synthesis techniques. The synthesis conditions were optimized to produce high surface area cobalt oxide nanopowders. Effect of precursors ratio on product properties (such as crystalline structure, nanoparticle size, surface area etc.) were studied and compared for the two methods. Thermodynamic calculations along with TGA/DTA studies were used to understand the synthesis mechanism leading to cobalt oxide formation. The synthesized nanopowders were characterized using various materials characterization techniques such as XRD, SEM and TEM. 相似文献
20.
Satoshi Uchida Tsugio Sato Akitsugu Okuwaki 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,57(3):221-227
The oxidation behavior of iron powder with oxygen was investigated in 5–25 m NaOH solutions at 5 MPa of oxygen partial pressure and 130–290°C, where m = mol(kg H2O)?1. Monodispersed micaceous iron oxide, α-Fe2O3, was synthesized by the oxidation of iron powder with 5 MPa of oxygen in 10–16 m NaOH solutions at 250–270°C. The diameter of micaceous iron oxide greatly changed depending on the reaction conditions such as the temperature, reaction time and concentrations of NaOH and coexisting ions. 相似文献
